1. Field of the Invention
The present invention relates to a baseball or softball bat employing an elastic body for a hitting portion, and more specifically, it relates to a baseball or softball bat employing an elastic body for a hitting portion, improved in repulsiveness while maintaining durability.
2. Description of the Background Art
A bat improved in repulsiveness by employing an elastic body for a hitting portion is known in general (refer to Japanese Patent Laying-Open No. 2002-126144 (hereinafter referred to as Patent Document 1), for example). In Patent Document 1, a hitting portion of a bat is constituted of a hitting portion core, an elastic body arranged on the outer periphery of the hitting portion core and a pipe as an outer shell member arranged on the outer periphery of the elastic body. Thus, the elastic body is compressed in batting by an impact resulting from the batting, so that a ball and the outer shell member move toward the direction of the hitting portion core. It is stated that the ball and the outer shell member thereafter move in the outer surface direction of the bat due to restoration of the elastic body, whereby the ball does not remarkably deform in the batting, and repulsiveness of the bat is improved by reducing energy loss resulting from deformation of the ball.
As a result of studying the aforementioned conventional bat, however, the inventor has found the following problem: In other words, while it is necessary to maintain a certain degree of strength in the outer shell member in the bat having the aforementioned structure, the outer shell member does not sufficiently deform or move in batting when the outer shell member of such sufficient strength is employed, and the improvement in the repulsiveness of the bat has been insufficient as a result. On the other hand, while a countermeasure of reducing rigidity of the outer shell member or employing a material softer than ever as the elastic body is conceivable in order to sufficiently deform the outer shell member or the elastic body in batting in the bat having the structure disclosed in Patent Document 1, such a new problem arises in this case that the durability of the bat lowers to deteriorate the batting feeling.